# US 8,541,542 B2 · Process for reducing residuals content in vinyl aromatic polymers

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- Number: US 8,541,542 B2
- Document ID: US8541542B2
- Status: Granted
- Kind: B2
- Application number: 12/374,807
- Filed: 2007-07-13
- Published: 2010-05-06
- Granted: 2013-09-24
- Earliest claimed: 2006-07-26
- Assignees: Total Research & Technology Feluy
- Applicants: Thomas-Maurice Roussel; Bruno Vuillemin; Francois Fajula
- Inventors: Thomas-Maurice Roussel; Bruno Vuillemin; Francois Fajula
- Web page: https://patentgrep.com/patent/US8541542B2

## CPC

- C08F 12/08: Styrene
- C08F 6/006: {Removal of residual monomers by chemical reaction, e.g. scavenging}
- C08F 212/08: Styrene
- Y10T 428/31794: Of cross-linked polyester
- Y10T 428/31804: Next to cellulosic
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention relates to a process for reducing residuals content in a vinyl aromatic polymer, said residuals comprising essentially unpolymerized vinyl aromatic monomer, wherein the vinyl aromatic polymer in the molten state is brought in contact with a solid in powder capable to catalyze the alkylation of said residual vinyl aromatic monomer on the vinyl aromatic polymer. Advantage of the present invention is a sharp reduction of the unpolymerized vinyl aromatic monomer in the vinyl aromatic polymer without generating a new residual and without inducing a colored vinyl aromatic polymer. The present invention also relates to said vinyl aromatic polymer having a low residuals content.

## Claims

### Claim 1

A process for reducing residual vinyl aromatic monomer in a vinyl aromatic polymer comprising:
contacting a molten vinyl aromatic polymer comprising residual vinyl aromatic monomer with a solid powder to catalyze alkylation of the residual vinyl aromatic monomer downstream of a devolitization section of a vinyl aromatic monomer polymerization facility.

### Claim 2 (depends on 1)

The process of claim 1, wherein the vinyl aromatic polymer comprises:
from 60 to 100 weight % of one or more C8-12 vinyl aromatic monomers; and
from 0 to 40 weight % of one or more monomers selected from the group consisting of C1-4 alkyl esters of acrylic or methacrylc acid and acrylonitrile and methacrylonitrile, wherein the vinyl aromatic polymer may be grafted onto or occluded within from 0 to 20 weight % of one or more rubbery polymers.

### Claim 3 (depends on 1)

The process of claim 1, wherein a particle size of the solid powder is from 5 nm to 200 μm.

### Claim 4 (depends on 1)

The process of claim 1, wherein the solid powder has a specific area higher than 100 m2/g.

### Claim 5 (depends on 1)

The process of claim 1, wherein the solid powder is absent porosity.

### Claim 6 (depends on 1)

The process of claim 1, wherein the solid powder exhibits a pore size of from 1.8 nm to 20 nm.

### Claim 7 (depends on 1)

The process of claim 1, wherein the solid powder comprises silica-alumina.

### Claim 8 (depends on 7)

The process of claim 7, wherein the solid powder is selected from amorphous silica alumina (ASA), crystalline silica alumina (CSA) and fumed silica alumina (FSA).

### Claim 9 (depends on 7)

The process of claim 7, wherein the solid powder exhibits an atomic ratio of Si/Al of from 2.5 to 150.

### Claim 10 (depends on 1)

The process of claim 1, wherein the solid powder exhibits an acidity of less than 9.

### Claim 11 (depends on 1)

The process of claim 1, wherein the solid powder exhibits an acidity of from 3 to 6.